Field of the Invention
The invention relates to a ratcheted lashing strap assembly containing a lashing strap that can be wrapped around the goods to be cinched, and a tightening device for the lashing strap. The tightening device includes a frame and a rotatable winding drum, in particular driven manually, in the frame for winding up the lashing strap. A fixation end of the lashing strap is in the form of a loop that grips a retention strut firmly attached to the frame and oriented parallel to the axis of the winding drum. An eye of the loop is penetrated by a support strut extending approximately parallel to the retention strut. An end run of the lashing strap, adjoining a loop base, is fixed, by clamping by the support strut, between the loop and the lashing strap. One such lashing strap is known from German Patent DE 28 45 227 C (see FIG. 3 in particular).
In the known ratcheted lashing strap assembly, the tightening device is a manually actuatable xe2x80x9ctension ratchetxe2x80x9d. This is preferably the case in the subject of the invention as well. In this reference, the fixation of the fixed end of the lashing strap, that is, the end opposite the cinching end wound onto the winding drum, is accomplished by two parallel bolts positioned side by side that are stationary in the housing. The two bolts are the retention strut and the support strut disposed parallel to the retention strut. Both struts are solidly connected to other parts of the frame. As fixed components of the frame, they form a unit with it.
The fixation of the fixed end of the lashing strap in the previously known tension ratchet is a clamping fixation. It thus avoids the usual seam connections between the upper run and lower run of the strap region that forms the curve of the loop, and in the relieved state it enables a variable preadjustment of the length of the lashing strap.
For its fixation on the frame, the fixation end of the lashing strap is wrapped around both the retention strut and the support strut extending parallel to it. Because of the invariable stationary fixation of the two struts in the frame, the operation involves threading something in, which requires special manual skill and attention on the part of the worker. Only when there is an exact relative position of the upper run and lower run of the end of the band relative to the retention strut and to the support strut is a secure clamping fixation assured. The security of the clamping fixation is indispensable, for reasons of job safety (protection of personnel).
From U.S. Pat. No. 5,933,923, a strap tightener for securing a strap around a load is known. The strap tightener has four pins mounted parallel to one another on a frame. Each two pins form a pair of pins, with one fixed pin and one movable pin. For securing the strap webbing, the strap is wrapped in a loop around the pins of one pair of pins at a time. The strap webbing is fixed to the strap tightener solely by the loop and the friction generated by the loop. Moreover, prestressing the strap tightener requires an additional device.
Published, Non-Prosecuted German Patent Application DE 88 09 854 A shows a strap connector on the end of a tension strap for securing loads. Once again, the strap webbing is disposed in a loop around two parallel bolts in a housing. For threading in the end of the strap, individual bolts can be removed from the housing, which makes handling the strap connector much simpler. If strap webbings of comparatively very slight thickness are used, three axially parallel bolts are provided as retention ribs. Here again, the fixation of the strap webbing is done solely by the friction generated by the loop.
It is accordingly an object of the invention to provide a ratcheted lashing strap assembly that overcomes the above-mentioned disadvantages of the prior art devices of this general type, in which a secure clamping fixation of the fixed end of the lashing strap to the frame is facilitated in terms of manipulation.
With the foregoing and other objects in view there is provided, in accordance with the invention, a ratcheted lashing strap assembly. The lashing strap assembly contains a lashing strap for wrapping around goods to be cinched and a tightening device engaging the lashing strap. The tightening device has a frame, a rotatable winding drum for winding up the lashing strap and supported in the frame, and a retention strut firmly attached to the frame and oriented parallel to an axis of the rotatable winding drum. A support strut extends substantially parallel to the retention strut. The lashing strap has a fixation end in a form of a loop gripping the retention strut and disposed remote from the rotatable winding drum. The loop has a loop base and an eye penetrated by the support strut. The support strut protrudes as a separate component from the tightening device. The support strut has ends protruding from the eye of the loop and are braced on the frame. The support strut is disposed on a side of the retention strut opposite the rotatable winding drum, and the support strut assumes a variable distance from the retention strut. The lashing strap has an end run adjoining the loop base. The end run is fixed between the loop and the lashing strap by clamping by the support strut.
The support strut is embodied as a separate component from the tightening device and protrudes by both ends from-the eye of the loop, and with the two ends it is merely braced on the frame, on the side of the retention strut opposite the winding drum, and therefore rests, in the relieved state of the lashing strap, in a way that can be easily released at any time. The support strut assumes a variable spacing from the retention strut.
As a result, the retention strut but not the support strut is solidly connected to the frame of the tightening device. Wrapping the fixation end of the lashing strap around the retention strut can be achieved without problems, since access to the retention strut is notxe2x80x94as in the known tightening devicexe2x80x94hindered by the support strut fixed in stationary fashion beforehand. The use of the ratcheted lashing strap of the invention enables simple, secure fixation of the fixed end of the lashing strap.
Especially the fixation end of the ratcheted lashing strap, that is, the eye of the loop put in place, that is wrapped to make a loop and therefore is intrinsically harder to manipulate, can be wrapped more easily around the retention strut, which according to the invention is accessible from outside freely and without hindrance. The support strut that forms a separate single part is easily inserted first into the eye of the loop, that is, thrust through from the side, once the eye of the loop has already been wrapped around the retention strut. The shape of the loop itself can be adapted to the support strut during the fastening process. Only after that is the lashing strap fixed to the frame with the aid of the support strut. Maintaining the spacing of the support strut, with its two ends protruding from the eye of the loop, relative to the retention strut is done either directly by the frame or indirectly by separate spacer elements, fundamentally automatically, and in a manner that is stationary, particularly under the tensile load on the lashing strap.
A contact position of the ends of the support strut on the frame, or more generally their bracing relative to the retention strut, can likewise be secured or perpetuated in an easily releasable fashion by a snap connection between the bracing or contact parts. The snap connection can be achieved by simple shaping provisions on the frame of the tightening device. Such a snap connection is a familiar machine element that can be made in various embodiments (see the reference by Bauer, titled xe2x80x9cHandbuch der verbindungstechnikxe2x80x9d [Manual of Connection Technology], Carl Hanser Verlag Mxc3xcnchen Wien, 1991, ISBN 3-446-14609-1, pages 294-324).
The ratcheted lashing strap of the present invention can be produced simply and economically. It meets the most stringent possible demands. Breaking strengths of up to 5000 daN are achieved with a standard ratchet.
The later insertion of the support strut into the eye of the loop wrapped around the retention strut is facilitated, in that the support strut rests circumferentially with a loose clearance fit in the eye of the loop. Under cinching tension, the support strut then assumes a position that is determined by the strap thickness of the lashing strap selected for the particular ratcheted lashing strap assembly, and thus with the ratcheted lashing strap assembly of the invention, lashing straps of the most various thicknesses can be used.
Once the lashing strap is securely fixed, the position of the loop is also fixed. The ensuing tightening of the lashing strap is thus accomplished especially securely.
The safety of the clamping connection between the fixed end of the lashing strap and the frame of the tightening device, and in particular the tension ratchet, is increased if the retention strut is surrounded by an approximately hollow-cylindrical sleeve with a loose clearance fit. The encasing sleeve compensates for different strap thicknesses and under cinching tension rests firmly against the clamped lashing strap. It is especially advantageous if the cross-sectional shape of the sleeve is variable under the influence of the circumferential pressure exerted under cinching tension by the doubled region of the strap, or in other words adapts to the loop. Under cinching tension, the sleeve assumes a cross-sectional shape (i.e. teardrop shaped) that effectively prevents rotation of the encasing sleeve. Protective-clamping is effected over a larger surface area region than in the case of two strap bolts that are not deformable under load. At the same time, the increase in clamping surface area is further promoted by the loose clearance fit of the sleeve on the retention strut. The encasing sleeve is preferably formed from steel and coated with zinc and/or chromium.
Embodying the two ends of the support strut as bearing pegs, with a cross-sectional dimension or peg diameter that is reduced compared to the support strut cross section or the support strut diameter has the advantage that the two vertical legs of the U-shaped sheet-metal part are kept spaced apart from one another by the steps between the support strut and the terminal bearing pegs, and this is true even under high cinching tension. The legs of the u-shaped frame support both the winding drum and the retention strut. As a result, a frame of stable shape can be produced economically by deformed sheet metal, even if the tightening device is to be used for high cinching forces. The separate, intrinsically loose support strut therefore not only has an important function in assuring the clamping of the cinching end of the lashing strap but also for stabilizing the shape of the frame of the tightening device.
The snap fixation, already described earlier herein, between the support strut and the frame can be produced simply, especially if sheet metal is used as a frame former, by stamping technology, through recesses in the end edges of the legs of the U-shaped frame. The recesses serve to put the ends of the support strut in place and thus provide a secured locational positioning of the support strut in its desired position. This results in a form-locking connection between the legs and the support strut.
The support strut, for reasons of manipulation, should also be retained as much as possible in a fixed position parallel to the retention strut. This can be assured on the one hand by a suitable embodiment of the frame but on the other by separate retaining elements. The retaining elements are embodied, structurally expediently, as retaining disks, which are threaded onto the retention strut and are thereby positioned in a simple way in their desired position relative to the retention strut. The positional fixation of the support strut after it has been threaded into the retaining loop can also be done at the retaining elements or retaining disks by a snap connection that is then provided there.
Advantageously, the support strut can also be coated on its circumference with a plastic. The coating can promote the safety of the positional fixation of the support strut to the frame or to the retention strut. The plastic coating can, however, also serve to cover production variations of the support strut, which can be a stamped, turned or forged part. Moreover, such a coating favorably affects the friction in the system. Instead of a snap connection, a clamping connection is also conceivable.
The support strut can be connected to the frame in a form-locking or force-locking manner. A form-locking connection is one that connects two elements together due to the shape of the elements themselves, as opposed to a force-locking connection, which locks the elements together by force external to the elements. A force-locking connection is one that connects two elements together by force external to the elements, as opposed to a form-locking connection, which is provided by the shapes of the elements themselves.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a ratcheted lashing strap assembly, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.